libgui: Add pre-MR2-compatible symbol for setPosition

SurfaceControl::setPosition now takes floats instead of integers as
arguments, which breaks linkability from pre-MR2 blobs. Add a direct
compatibility wrapper, since the values are treated in the same
way.

Change-Id: I0fd0708faeb4495a2dbbb659997d6500f165ec98
Merge pull request #3 from CyanogenMod/cm-10.2

libgui: Add pre-MR2-compatible symbol for setPosition